A flow cell reactor for the study of growth kinetics of single hairy roots

Abstract

A flow cell reactor designed for the study of growth and branching of individual roots under defined fluid flow conditions is described and preliminary results with the hairy root clone Tagetes erecta T3 are presented. Observations of root growth in this reactor may help to formulate and verify mathematical models root growth kinetics.Introduction.

The growth of single roots ofArtemisia annua in nutrient mist reactors

“…Sometimes the roots became brown at the tip or somewhere along the length and, when this happened, the roots often produced lateral branches severals days later and began growing again. A similar response was observed in the liquid flow cell experiments of Flint-Wandel and Hjortso (1993) where the primary tip died and lateral branches continued to elongate and remain healthy. Despite the differences in morphology and viability observed during the three misting cycles, a single-factor analysis of variance of all of the data sets found no significant difference in (L − L 0 )/L 0 for these three conditions at the 95% confidence level.…”

Population Balance Approach to Modeling Hairy Root Growth

“…Finally the growth rate slows probably as the result of a combination of tip death and the depletion of oxygen and other nutrients (7,19). Hairy root cultures grown in continuous bioreactors also show the same three growth phases (4,6). However, in this case the decrease in the growth rate of the culture in the mature phase is probably due to tip death and oxygen and nutrient limitations at the surface of branches at the center of the culture cell due to increased mass transfer resistance.…”

“…Clearly, Figures 3 and 4 indicate the existence of the three growth phases mentioned above. (2), and C. roseus (9) is given in fresh weight and should be read using the left-hand side y-axis, while the biomass of T. foenum-graecum ()), D. carota (4), and Ajuga sp. (0) is given in dry weight by the right-hand side y-axis.…”

“…(b) Variation of specific growth rate with time for hairy root cultures where the biomass is reported as dry weight. The specific growth rate for D. carota (4) and Ajuga sp. (0) should be read using the left-hand side y-axis while data for T. foenum-graecum ()) is read using the right-hand side y-axis.…”

Inhibitory role of root hairs on transport within root culture bioreactors

“…The scanned images of typical roots, also shown in Figure 1, support this. A further assessment of morphology was conducted by calculating the branching ratio as defined by Hjortso and colleagues (Flint-Wandel and Hjortso, 1993) which is a measure of the distances between primary and secondary branches. For cultures in the presence and absence of PBA these ratios were not statistically different (95%, t-test), with a mean ± standard deviation of 18.4 ± 7.0 (n ‫ס‬ 8).…”